Many systemic and metabolic diseases are associated with increased risk factors that promote the development of thrombus. But early diagnosis of thromboembolism (TE) may difficult in general practice due to a lack of noninvasive diagnostic tests. This study was conducted to compare the plasma concentration of D-dimer, platelet numbers and fibrinogen degradation products (FDPs) between healthy and clinically ill dogs to evaluate the usefulness of these assays in detections of hypercoagulability. Eighty-one clinically ill dogs with high risk of TE and 25 healthy dogs were included in this study. The plasma D-dimer concentrations were measured through the immunometric assay, and FDPs concentration was measured by semi-quantitative latex agglutination assay. Results of the present study indicated D-dimer concentrations were mainly elevated in immune-mediated hemolytic anemia (IMHA), liver disease, neoplasia and miscellaneous inflammatory disease group. In addition, markedly increased D-dimer concentrations (>2000ng/ml) were also mostly presented in IMHA (33.3%), liver disease (20%), and neoplasia (14.3%) group. Platelet numbers were significantly different only in neoplasia and endocrine disorder group. The plasma concentrations of D-dimer and FDPs of clinically ill dogs were mainly increased compared to healthy dogs. However, almost 30% of dogs with normal D-dimer value showed positive FDP assay results in both healthy and disease group. Concurrently performed plasma D-dimer and FDPs assays can be rapid screening tests for hypercoagulability in canine patients; however, cautious interpretation is required and should not be used as single diagnostic tool for TE.

Key words: D-dimer, Fibrinogen degradation products, Hypercoagulability, Thromboembolism